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Author Topic: Why can't once-related populations interbreed?  (Read 3362 times)

Matthew Hodge

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Why can't once-related populations interbreed?
« on: 22/07/2010 11:30:02 »
Matthew Hodge  asked the Naked Scientists:
   
Hi Chris, Dave, Kat and the rest of the Naked Scientist team,

I love your programme!  Great diversity in topics and very accessible level of discussion.

My wife bought me a ipod for my birthday and then I discovered "THE NAKED SCIENTIST" I'm up to mid 2009 in your Podcast listing

I have a question you could slot into a show related to genetics.

Question: What is the difference at the genetic level between to identical groups of animals, then evolving separately, that then prevents them producing fertile offspring?

So by definition what prevents inter species breading?

Fanciful Example 1: There is a island populated with a particular snake on it and an earthquake splits the island in two. Due to the extinction of some predators and plants on one island, the two snake groups evolve different colouration, size and venom. Then another freak earthquake joins the two islands, now both snakes would be benefit from a mix of colour size and venom. Why wouldn't the genes allow this re-blending?        

Fanciful Example 2: brightly coloured parrot mates with similar parrot and obtains new colour variation favorable to attracting mate.

Fanciful Example 3: polar bear mates with brown bear to produce mottled bear better suited to changing environment. Potentially brown bear obtains strength and size genes of polar bear and polar bear gets good colour variation and varied diet suitability.

Fanciful Example 4: People go to Mars and start new life, 1000 years pass and they return to earth can the earthlings mate successfully with the martians?

How does this tie into un-natural selection (Domestic), feral/pest evolution, hybrid species?

If small random mutations may slowly produce adaptions to a particular environment, then a particular organism could mate with an animal with an already developed "mutation" and very quickly be adapted to a new environment? I suppose at a genetic level it would have to be beneficial to both parties. 

I would love to here your thoughts and input on this topic.

Best Regards,

Matt Hodge.

What do you think?
« Last Edit: 22/07/2010 11:30:02 by _system »


 

Offline Jolly- Joliver

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Why can't once-related populations interbreed?
« Reply #1 on: 29/03/2011 19:06:56 »
Matthew Hodge  asked the Naked Scientists:
   
Hi Chris, Dave, Kat and the rest of the Naked Scientist team,

I love your programme!  Great diversity in topics and very accessible level of discussion.

My wife bought me a ipod for my birthday and then I discovered "THE NAKED SCIENTIST" I'm up to mid 2009 in your Podcast listing

I have a question you could slot into a show related to genetics.

Question: What is the difference at the genetic level between to identical groups of animals, then evolving separately, that then prevents them producing fertile offspring?

So by definition what prevents inter species breading?

Fanciful Example 1: There is a island populated with a particular snake on it and an earthquake splits the island in two. Due to the extinction of some predators and plants on one island, the two snake groups evolve different colouration, size and venom. Then another freak earthquake joins the two islands, now both snakes would be benefit from a mix of colour size and venom. Why wouldn't the genes allow this re-blending? 

I think your question is why cant evolutionarily seperated animals form the same family have offspring, like asking why cant the crow have offspring with the magpie, as they once shared an ancester.

I believe in certain circumstances life from the same family tree can, Looking a extreme types of dog and cat. When is the evolutionary shift so extreme that the possiblity ends? Is an interesting question and I suppose the answer might be slightly different for each member of the tree you look at.
       

 

Offline Dasyatis

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Why can't once-related populations interbreed?
« Reply #2 on: 21/04/2011 21:25:21 »
There are many reasons why this could happen. Some of the fanciful examples you give could actually happen in nature, but what would keep them from breeding successfully?

Without any genetics at all here are some possibilities: 1) it could possibly be that the animals simply no longer display attractive qualities (color, behavior, odor, etc.). These traits often aid females in finding males of the right species, and thus if any of those traits are changed, it could lead to failed mating attempts; 2) Reproductive timing can be quite sensitive if species are separated by several degrees of latitude, and so if the two species come back together they may not breed at the same time; 3) somehow the speciation caused the "parts" to no longer fit properly.

With genetics in play there are other possibilities: 1) The sperm and the egg lead to failed embryonic development due to genetic incompatability (i.e. the genes don't give the right instructions at the right time to complete development), which prevents the offspring from ever becoming anything more than a fetus; 2)The hybrid is inviable (i.e. too weak to survive to reproductive age); 3) The hybrid is sterile.
 

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Why can't once-related populations interbreed?
« Reply #2 on: 21/04/2011 21:25:21 »

 

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